Problem: Evaluate $2-(-4)+(-y)$ where $y = 7$.
Explanation: Let's substitute ${y = 7}$ into the expression. $\begin{aligned} &\phantom{=} 2-(-4)+(-{y}) \\\\ &= 2-\left(-4\right)+\left(-{7}\right) \end{aligned}$ $\begin{aligned} &= 2+4-7 \\\\ &=6-7 \end{aligned}$ $=-1$